Cans are generally used for perishables. Before the contents of the can are cooked by heating, the can is opened so that the contents can be withdrawn therefrom. Some canned beverages are dispensed by a vending machine which keeps the cans warm, but they will eventually be cooled if they are not drunk immediately. Hence, it is necessary for hikers or climbers to separately bring portable fuel in order to heat or warm any canned foods or canned beverages which they have brought with them.
Although heaters such as portable fuel and portable cookers are widely known, it is troublesome to carry these heaters along with food, and also laborious to cook the food with such a cooker.
To simplify the cooking of food, various instant meals which only require the pouring of hot water are also known, but the above-described heaters are still necessary in order to obtain the hot water in the first place, when cooking such instant meals outdoors.
In a portable heater, a container to be heated is mounted on a support metal fixture provided on a burner, or is inserted into the support metal fixture so that it can be engageably supported. However, this type of support structure encounters a problem that the heated container may fall from the support when the heater is moved.
Meanwhile, there is a demand for a lightweight compact portable heater possessing the necessary strength to hold a burner, a container to be heated, a fuel tank, and the like.
When a heater is operated, the heater must utilize a limited amount of fuel gas as efficiently as possible, and hence the heater should be superior in operability and functionality.
Also, when a combustion duct is provided to direct a combustion gas so that a heat efficiency of the heater can be improved, it becomes difficult to handle this duct when it is heated.
In order to improve a combustion efficiency, it is necessary to take air for combustion purposes into the heater. However, the combustion of the heater may be obstructed by a backfire, that is, a spurt of flames out from an opening, the flames produced by the ignition of gas filled inside the heater, or by inflow of wind from outside.
In the case of a heater equipped with a burner at the bottom end thereof, the heater suffers several drawbacks in its ignition operations.
On the other hand, the supply of gas from a fuel tank is affected by a latent heat of the gas when it evaporates, so that the supply becomes unstable. The supply of gas also becomes unstable due to atmospheric temperature, and hence the heater experiences unstable combustion.
In view of the foregoing descriptions and observations, an object of this invention is to provide a portable heater which can easily cook canned food anywhere directly without opening the can before the contents of a container are heated; which can directly heat a canned beverage anywhere; and which is compact and lightweight, and has sufficient strength, and provides a stable combustion with a high heat efficiency and a superior operability.